(a.) Fleeting; lasting but a short time; volatile -- applied to parts which are short-lived as compared with the life of the individual\.

brittle capricious changeable corruptible deciduous dying ephemeral evanescent fading fickle fleeting flitting fly-by-night flying fragile frail fugitive impermanent impetuous impulsive inconstant insubstantial momentary mortal mutable nondurable nonpermanent passing perishable short-lived temporal temporary transient transitive transitory undurable unenduring unstable volatile